Chitosan dual gel-like functionalized with flavonoid extract and cinnamaldehyde oil using dual cross-linking agents: Characterization, antioxidant, and antimicrobial effects

This study evaluated antioxidant and antimicrobial properties of chitosan gel (Cs-gel) functionalized with cinnamaldehyde oil (CN) and orange peel-derived flavonoid extract (Fs) using the ionic-gelation method. Results showed that the encapsulation efficiencies of CCF-9 and CCN were 83.14 ± 3.34 and 80.56 ± 1.17%, respectively. The interaction of CN or Fs on Cs-gel indicates the presence of H-bonding formation, as observed by UV–vis spectroscopy, Fourier transform infrared spectrophotometry (FTIR), and Raman-spectroscopy showed a good corroboration with Surflex-dock findings. Scanning electron microscopy also showed the integration that occurred between Cs and both ligands, which was further supported with X-ray diffraction and X-Ray photoelectron spectroscopy spectra. The textural properties of CCF-5 gel showed high hardness, chewiness, and gumminess values, indicating that the integration of Fs and CN altered the microstructure of Cs-gel. Chotison-functionalized based gels exhibited higher antioxidant abilities against DPPH and ABTS free radicals than Cs-gel. The CCF-9 gel showed a good inhibition value of 29.91 ± 1.22 and 93.61 ± 2.12% against Penicillium expansum and Alternaria westerdijkiae, respectively. Additionally, CCF-9 inhibition zones against Staphylococcus aureus, Escherichia coli, and Bacillus cerues were 28.65 ± 0.05, 27.69 ± 0.04, and 26.16 ± 0.02 mm, respectively. These findings demonstrated the potential antioxidant and antimicrobial effects of functionalized chitosan gel indicating its potential as a bioactive additive for food preservation.